Ribbon reverse mechanism



' Sept. 30, 1941.

J. A. HEPT RIBBON REVERSE MECHANISM Fi1ed Feb. 5, 1941 2 Sheets-Sheet l ATTORNEY Sept. 30, 1941. J. A. HEFT 2,257,553

RIBBON REVERSE MECHANI SM Filed Feb. 6, 1941 2 Sheets-Sheet 2 INVENTOR J/ZHe vi ATTORNEY Patented Sept. 30, 1941 UNITED STATES PATENT OFFICE RIBBON REVERSE MECHANISM Application February 6, 1941, Serial N 0. 377,642

Claims.

This invention relates to a ribbon reverse mechanism for a typing machine such as a typewriter or teletypewriter or the like, and is more particularly applicable to teletypewriter machines.

ln a machine of the character above referred to the ribbon is wound upon one spool and is gradually unwound from that spool and wound upon another spool as the typing operation proceeds. When the ribbon approaches its end it operates a reversing mechanism which causes the ribbon to be unwound from the secondspool and again rewound upon the first spool. This result is accomplished by having associated with each spool a ribbon reverse arm mounted upon a ribbon reverse shaft which operates the reversing mechanism. The ribbon reverse arm is usually provided with a slotted arrangement through which the ribbon passes, and as the ribbon approaches the end, a button or eyelet in the ribbon engages the reverse arm to rotate the reverse shaft through a small arc and therebycause' the reverse mechanism to operate.

There is, of course, a reverse arm and shaft associated with each ribbon spool, and it has been found in practice that occasionally an at tendant, desiring to change the ribbon inadvertently moves one or the other of the ribbon reverse arms through a greater are than it is intended to operate. This results in either mov- 1 ing the reverse arm with respect to the ribbon reverse shaft upon which it is mounted or else the reverse shaft is moved with respect to the lever clamped thereto at its bottom and which serves to operate the reversing mechanism. In either case .the reversing mechanism is out of adjustment and does not operate properly.

- The object of the present invention, therefore, is to provide a yielding arrangement in the ribbon reverse mechanism so that when the attendant inadvertently applies pressure against the ribbon reverse arms, slippage of theparts clamped to the ribbon reverse shaft will not occur.

The invention will now be more fully under? shaft; Fig. 5 is a perspective view of a portion of the type bar carriage of a teletypewriter showing particularly parts of the ribbon reversing mechanism as seen generally from the rear; Fig. 6 is a broken plan view, looking from above, of the ribbon spool cups with the ribbon spools mounted therein and of the ribbon shield and the associated ribbon reverse arms; Fig. 7 is a side view of a ribbon spool cup and its associated ribbon reverse arm together with certain other elements of the reversing mechanism; and Fig. 8 is a perspective view looking generally toward the bottom of the type bar carriage and showing parts of the ribbon reverse mechanism.

Referring to the drawings and particularly Fig. 5 thereof, portions of a main frame I for a type bar carriage are shown. Upon this frame aspacing rack 2 is mounted, the latter serving to move the type bar carriage step by step by means of a ratchet mechanism as the letters are printed. A type bar segment 3 is mounted on the front side of theframe I (Fig. 5 is a view looking from the rear) which is provided with a bearing rod 4 mounted in' a suitable longitudinal groove and functioning as the pivot about which type bars such as 5 are caused to swing when actuated by a pull bar 6 in a well known manner. The various type bars and their associated pull bars are mounted to operate in parallel slots 1 in the type bar segment 3. The pull bars are held in their rearward position by means of coiled springs such as 8.

In front of the frame I but to the rear and above the type bar segment 3 a bracket 9 is j mounted, said bracket having arms upon which the. arms of a ribbon shield I 0 are mounted to slide up and down. The arms of the ribbon shield l0 have slotted members II and II" through which the ribbon l2 passes in such manner that it may be stretched in front of a platen (not'shown during the printing operation. The ribbon shield It may be operated by means of a ribbon oscillator l2 in such a manner that after the character has been printed the ribbon shield is moved downwardly to pull the ribbon below the point on the platen at which the character was printed, thus enabling the operator to view the printed character.

Referring to Figs. 7 and 8, U-shaped brackets l3 and I3 are suitably mounted on projections such as M of the frame I, as more clearly shown in Fig. 8. On the upper arms l5 and I5 of the bracket l3 and I3, respectively, ribbon spool cups l6 and I6 are rotatably mounted as shown in Figs. 5, 6 and 8. The pivotal mountings of these cups have attached thereto on the opposite sides of the bracket arms l5 and I5 pinion gears I! and I1 respectively. These mesh respectively with pinion gears I8 and I8 mounted upon vertical ribbon feed shafts I9 and I9 respectively. At the lower end of each of these shafts are beveled gears 23 and by means of which the shafts may be rotated to in turn rotate the ribbon spool cups l6 and Hi.

The ribbon I2 is wound upon ribbon spools 2| and 2|. As shown in the drawing the ribbon is being unwound from the spool 2| and being rewound on the spool 2|. By reason of the fact that the beveled gear 23' is in mesh with a beveled gear 22 carried upon a ribbon feed shaft 23, at the opposite end of which is'another beveled gear 22, the beveled gear 22 is not,as

shown, in mesh with its corresponding beveled. gear 29 on the vertical feed shaft Ill. The ribbon feed shaft 23 carries a ribbon feed shaft gear 24 which is in mesh with a ribbon feedratchet gear 25. The latter is mounted on the same shaft with a ribbon feed ratchet 26 which is moved step 7 by step by a pawl 21, the latter being operated by a plunger 28through the medium of a lever 29. The plunger 23 is slidably mounted in the'main frame I so that it is moved backward and forward (up and down in Fig. 8) each time a character is printed. As a consequence, each time a character is printed the pawl actuates the ribbon'feed ratchet 2'3 one step. Thus the ribbon feed shaft 23 is rotated one step for each character audit in turn rotates the vertical ribbon feed shaft, l9, one step for each character. Thi action'continues until the ribbon is substantially unwound from the ribbon spool 2 I and,

is substantially fully wound upon the ribbon spool 2|, when a ribbon feed reversal takes place.

The mechanism for reversing the ribbon feed includes 'two' ribbon reverse arms 30 and 3|! yieldably mounted on the upper ends of ribbon reverse shafts 3| andgSl in a manner that will be described later. At the'lower'ends of the ribbon reversing shafts 3| and 3|, short U- shaped arms or levers 32 and 32 are respectively fixed by means of set screws. From each of these arms r levers links 33 and 33 extend respectively to reverse pawls 34 and 34' pivotally'mounted the ribbon reverse bail 31, carried by the oscillating bail plunger 28. Consequently, while the bail 3] is oscillated back and forth each time a character is printed, it cannot affect any ribbon reversing action until one or the other of the arms 33 or 3!) is actuated by the ribbon 12. In order the right so that its shoulder is engaged by the ribbon reverse bail 31 upon the next movement rearwardly (upwardly in Fig. 3) of the bail plunger 28. Upon this movement the end of the bail 3! engages the shoulder of the ribbon reverse pawl 34 and thereby rocks the rocker 35 about its pivot so as to rotate it in a counter-clockwise direction.

As a consequence, the upper part of the reverse arm'engages the back of the beveled gear 22 and moves the ribbon feed shaft 23 to the left, so that the beveled gear 22' becomes disengaged from the beveled gear 20' and the beveled gear 22 engages the beveled gear 20. As the shaft 23 is moved, ashoulder 39 mounted thereon is snapped past a roller 40 carried by a spring arm 4| so that the shaft 23 will be held in the shifted position.

When so shifted the shaft 23 is moved step by step by means ofithe pawl 21 and ratchet 26 each time a letter is printed. This causes the beveled gear 22, in mesh with the beveled gear 20, to drive the ribbon feed shaft l9, which acting through the pinion. gears I! and I8, causes the ribbon spool 2| to begin winding the ribbon thereon. As the ribbon I2 is wound upon the spool 2| it unwinds from the spool 2|.

When the ribbon is completely wound upon the spool 2|, an eyelet near the other end of the ribbon operates the. ribbon reverse arm 30', thus moving-the ribbon reverse pawl 34. to the left. As a consequence it is engaged by the end of the bail 31 upon the next movementof, the latter to.

rock the rockerarm 35' and shift the ribbon feed shaft 23 to the right, thus. reversing the operation and causing the ribbon to wind up on the spool 2 In removing the ribbon i2 and the spools 2| and 2| and replacing, them with a new ribbon and new spools, the attendant is apt to move one of the arms 30 or 30 further than it is intended to go, by inadvertently pressing against it with and 4. As shown in Figs. 1 and 2 the arm 3|!v is not fixed to the shaft 3| but is rotatably to actuate one of these arms the ribbon I2 is provided with eyelets such as 33 (see Fig. 6) at 7 either end thereof, and as the ribbon is unwound fromthe spool carried by the ribbonspool cup 16, for example, the eyelet; 38 engages the slotted end of the arm 33,'causing it to move in the direction of the guide about its ivot 3|.

As the arm 33 somoves it rotates the ribbon reverse shaft 3 I through a small are, thus shifting fixedly attached to the shaft by means of a stiff V coiled, spring 45. Consequently, asthe ribbon reverse arm 30 moves counter clockwise with respect to the shaft 3|, its arm 42 acting through the-spring 45 carries with. it the arm43 which isfixedly attached to the shaft3l; Thus the shaft 3| rotates in'a counter clockwise direction.

with the ribbon reverse arm 30,

'However, the operator in workingwith the ribbon may accidentally move the arm 30' counterclockwise further than it is intended to go, so that the shaft 3| in effect comes up against a stop. For example, if the ribbon reverse pawl 3 engages the bail 31, the spring 45' will begin to yield and permit the arm 30' with its associated arm 42 to continue to move in a counter clockwise direction. This it can do without causing any relative shifting, with respect to the shaft 3|, of either the arm 43 at the top of the shaft 3|, or the arm 32' at the bottom thereof. This yielding arrangement enables the ribbon reverse arms to be abnormally shifted without causing any maladjustment of the ribbon reverse mechanism. At the same time the arrangement permits the normal shifting of the ribbon reverse arm by means of the eyelet uponthe ribbon to cause a corresponding rotation of the ribbon reverse shaft without undue yielding of the coiled spring 45' or 45 as the case may be.

It will be obvious that the general principles herein disclosed may be embodied in many other organizations widely different from those illustrated without departing from the spirit of the invention as defined in the following claims.

What is claimed is:

1. In a typing mechanism, a ribbon, a pair of spools, means to gradually unwind said ribbon from one of said spools and Wind it upon the second spool, reversing mechanism to reverse the winding operation so as to rewind the ribbon upon the first spool, said reversing mechanism including a shaft for controlling the reversing operation, an arm associated with said shaft and engaging said ribbon, a member on said ribbon for moving said arm through a small arc to institute the reversal operation, and a yieldable connection between said arm and said shaft to permit an accidental movement of said arm greater than said small are without causing damage to or maladjustment of said mechanism.

2. In a typing mechanism, a ribbon, a pair of spools, means to gradually unwind said ribbon from one of said spools and wind it upon the second spool, reversing mechanism to reverse the winding operation so as to rewind the ribbon upon the first spool, said reversing mechanism including a shaft for controlling the reversing operation, an arm associated with said shaft and engaging said ribbon, a member on said ribbon for moving said arm through a small arc to institute the reversal operation, and a spring connected between said arm and said shaft to permit an accidental movement of said arm greater than said small arc without causing damage to or maladjustment of said mechanism.

3. In a typing mechanism, a ribbon, a pair of spools, means to gradually unwind said ribbon from one of said spools and wind it upon the second spool, reversing mechanism to reverse the winding operation so as to rewind the ribbon upon the first spool, said reversing mechanism including a shaft for controlling the reversing operation, an arm associated with said shaft and engaging said ribbon, a member on said ribbon for moving said arm through a small arc to institute the reversal operation, and a spring connected between said arm and an element fixed to said shaft to permit an accidental movement of said arm greater than said small arc without causing damage to or maladjustment of said mechanism.

4. In a typing mechanism, a ribbon, a pair of spools, means to gradually unwind said ribbon from one of said spools as typing takes place and wind it upon the second spool, said means including a driving shaft associated with each spool,

reversing means to selectively operate said shafts so that one shaft will be operated to wind said ribbon on one spool under certain conditions and the other shaft will be operated under other conditions to reverse the operation and wind the ribbon on the other spool, a reversing shaft associated with each spool for controlling said reversing operation, an arm associated with each of said reversing shafts and engaging said ribbon, means carried by said ribbon for selectively operating one or the other of said reversing shafts to move it through a small arc to institute the reversing operation, and a yieldable connection between said arm and said shaft to permit an accidental movement of said arm greater than said small are without causing damage to or mal adjustment of said mechanism.

JOHN ANTHONY HEPT. 

